1. Field of the Invention
The present invention relates to a displacement detection apparatus, and more particularly to a displacement detection apparatus which irradiates a light beam from a light source onto an object and detects incident position information on a predetermined plane of a reflected light beam from the object to determine displacement information (absolute position information) of the object from a predetermined position.
2. Related Background Art
Various displacement detection apparatuses which can photoelectrically detect displacement amount or displacement information from a predetermined position of an object by utilizing a light have been proposed.
FIG. 1 shows a schematic diagram of a prior art laser displacement apparatus which utilizes a laser beam.
In FIG. 1, a light beam 83 from a semiconductor laser 82 driven by a semiconductor laser drive circuit 81 is condensed by a projection lens 84 and projected so as to form a light spot on an object 85. A reflected light beam from the object is directed onto a light position detector 87 of such as a position sensor by a condense lens (receiving lens) 86.
When the object is displaced from a reference position C to a position A.sub.1 or a position B.sub.1, an incident position of the reflected light beam to the light position detector 87 changes to a point A' or a point B'. A displacement amount or a displacement information from a predetermined position of the object 85 is detected by using a signal from the light position detector 87.
In the prior art displacement detection apparatus, the light source portion, the projection lens and the light position detector and the like are independently arranged in a housing.
As a result, there have been problems that the number of parts increases, the assembly adjustment of the elements and the position adjustment among the elements are difficult to attain, and the overall size of the apparatus increases.